#include <bits/stdc++.h>
using namespace std;
long long n, p, q;
vector<int> a;
bool check(int x)
{
int l1, l2;
vector<vector<int>> dp(n+1, vector<int>(p+1, 1e9));
vector<int> L1(n+1), L2(n+1);
for (int i=0; i<=p; i++)
dp[0][i]=0;
for(int i=1; i<=n; i++)
{
l1=i, l2=i;
while(l1>0 && a[i]-a[l1]<x) l1--;
while(l2>0 && a[i]-a[l2]<2*x) l2--;
L1[i]=l1;
L2[i]=l2;
}
for(int i=1; i<=n; i++)
{
l1 = L1[i], l2 = L2[i];
for(int j=0; j<=p; j++)
{
//patara photo
if(j>0){
dp[i][j]=min(dp[i][j], dp[l1][j-1]);}
//didi photo
dp[i][j]=min(dp[i][j], dp[l2][j]+1);
}
}
if(dp[n][p]<=q) return true;
return false;
}
int main() {
// int n, p, q;
cin>>n>>p>>q;
a.resize(n+1);
for(int i=1; i<=n; i++)
{
cin>>a[i];
}
sort(a.begin()+1, a.end());
int l=0, r=100;
int ans=r;
while(l<=r)
{
int mid=(l+r)/2;// cout<<l<<" "<<r<<endl;
if(check(mid))
{
ans=mid;
r=mid-1;
}
else
l=mid+1;
}
cout<<ans<<endl;
}
